1. Field of the Invention
The present invention relates to a dental glass-ionomer cement composition and a method of preparing the same and, more particularly, to a dental glass-ionomer cement composition and a method of preparing the same, in which the dental glass-ionomer cement composition may exhibit increased initial strength while ensuring sufficient working time by a user.
2. Description of the Related Art
Dental glass-ionomer cement is characterized by high biocompatibility, strong adhesion to teeth, and a good esthetic appearance. Also, dental glass-ionomer cement is responsible for gradually releasing fluorine to thus strengthen the tooth structure, and is thus widely utilized in various dental fields. Dental glass-ionomer cement is composed mainly of a fluoroaluminosilicate glass powder and a polycarboxylic acid aqueous solution. More specifically, the polycarboxylic acid aqueous solution may dissolve the surface of a glass powder such as fluoroaluminosilicate, so that the metal in the glass, such as alkali metal, alkaline earth metal, or aluminum, is isolated as ions, and these ions are used to form an ionic bond with the carboxyl group of polycarboxylic acid to thus yield a cross-linked structure.
Typically, a glass ionomer includes an aqueous solution of a polyacrylic acid derivative as polycarboxylic acid and an inorganic filler comprising a fluoroaluminosilicate powder, and the above two materials are mixed immediately before use. Upon mixing, the protons in the aqueous solution infiltrate the inorganic powder, whereby the cations of the inorganic powder are substituted and released. The cations and the carboxylate anions of the polyacrylic acid derivative are subjected to an acid-base reaction to form a chelate, and thus setting occurs for a few minutes after mixing. Furthermore, fluorine, contained in a small amount in the inorganic powder, is gradually released over a long period of time, thus exhibiting cavity preventive effects.
Despite the above advantages, however, the glass ionomer has low initial strength, and the setting thereof wholly depends on the formation of the chelate, undesirably resulting in poor mechanical properties, and moreover, the setting reaction begins at the time of mixing, undesirably resulting in a working time as short as a few minutes.
With regard to the glass-ionomer cement composition, Korean Patent No. 10-0341142 (Jun. 20, 2002) discloses a novel polymerizable carboxylic acid (meth)acrylate monomer for dental restorative materials exhibiting improved mechanical properties and ease of use, a method of preparing the same, and a dental restorative composition including the same, and also, Korean Patent Application Publication No. 10-2014-0042751 (Apr. 7, 2014) discloses a fluoroaluminosilicate glass powder for increasing acid resistance of a dental glass-ionomer cement and a method of preparing the same.
Meanwhile, with the goal of solving the defects of the conventional glass ionomer, including low initial strength and poor mechanical properties, by using photopolymerization and acid-base reaction together upon setting, a resin-reinforced glass ionomer has been developed. Furthermore, a photocurable resin-reinforced glass ionomer has been developed, in which a mixture of an aqueous solution and inorganic powder is loaded in a tooth portion to be treated and is then irradiated with light to thus be cured.
However, the conventional techniques are problematic because the working time is still short, and many attempts are being continuously made to increase the initial compressive strength.